Method of detecting optical disk error information

ABSTRACT

A method of detecting optical disc error information on an optical disc, for applying in an optical disc drive, the method comprising: first, detecting whether the optical disc is blank, if not, perform the following: checking whether a seek error occurred, if yes, recording a seek error mark; while reading a data region, recording data error information, the data error information comprises an error count, and a corresponding data error location; finally, outputting the optical disk error information according to the data error information and the seek error mark.

This application claims the benefit of Taiwan application Serial No.093112830, filed May 6, 2004, the subject matter of which isincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates in general to a method of detecting errors, andmore particularly to a method of detecting optical disc errorinformation of an optical disc.

2. Description of the Related Art

Optical disc recorders nowadays have become very popular, where userscan easily back up their files, photos, audio and videos etc. Opticaldisc recorders have many varieties, such as CD-R/RW, DVD+R/RW, DVD-R/RW,DVD dual and DVD-RAM etc, and users record files onto optical discsaccording to the different standards associated with the optical discrecorders.

During the recording process, the optical pick-up heads of the opticaldisc recorders are to emit laser at the optical disk with varyingpowers, so that data bits 1 or 0 can be recorded on the optical discs.The problem associated with conventional applications is that whenoptical discs rotate at very high speeds during the recording process,the dye is not always stable or evenly distributed on the optical discs,as a result, data errors from recording inevitably occur.

With regards to CDs, the associated data errors can be classified intoC1 and C2, where C1 refers to data errors that can be recovered by meansof algorithms, while C2 refers to data errors that are unrecoverable.Thus, C1 data errors will not significantly affect the accuracy of therecorded data, but C2 will.

With regards to DVDs, the associated data errors are classified into PIand PO, where PI refers to data errors that can be recovered by means ofalgorithms, whereas PO refers to data errors that are unrecoverable.Thus, PI data errors will not significantly affect the accuracy of therecorded data, but PO will.

However, users are unable to distinguish between good and bad opticaldiscs, or even anticipate the quality of optical discs after beingrecorded. That is, users can only determine the quality of the opticaldiscs by whether the reading of the recorded optical discs wassuccessful, and are unable to know how frequent that C1, and C2, or PIand PO occur.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide a method ofdetecting optical disc error information on an optical disk.

The invention achieves the above-identified object by providing a methodof detecting optical disc error information on an optical disc, forapplying in an optical disc drive. The method includes: first, detectingwhether the optical disc is blank, if not, performing the followingsteps: checking whether a seek error occurred, if yes, recording a seekerror mark; while reading a data region, recording a data errorinformation, the data error information includes an error count, and acorresponding data error location; and finally, outputting the opticaldisk error information according to the data error information and theseek error mark.

The invention achieves another above-identified object by providing amethod of determining an optimal tilt angle for an optical pick-up head.The steps including: first, determining tilt angles, where the tiltangles are substantially different from one another; then, reading anoptical disc according to the each of the tilt angles; next, generatingoptical disc error information for each of the tilt angles; and finally,determining the optimal tilt angle according to the optical disc errorinformation.

Other objects, features, and advantages of the invention will becomeapparent from the following detailed description of the preferred butnon-limiting embodiments. The following description is made withreference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow diagram of a method of detecting optical disc errorinformation according to an embodiment of the invention.

FIG. 2A is a flow diagram illustrating the application of the inventionin a method of determining optical pick-up head tilt angles.

FIG. 2B shows a graph plotting the relationship between optical discerror information and tilt angles according to the data errors and tiltangles entries recorded for determining the optical pick-up head tiltangles.

FIG. 3 shows a flow diagram of a method of detecting address errorinformation on a blank optical disc.

DETAILED DESCRIPTION OF THE INVENTION

To acquire the manufacturing quality of blank optical discs, the addresserror information thereof is detected. Likewise, the compatibilitybetween recorded optical discs and optical disc recorders can beobtained by detecting data error information of the recorded opticaldiscs.

Referring to FIG. 1, a flow diagram of a method of detecting opticaldisc error information of a recorded optical disc according to anembodiment of the invention is shown. In this embodiment, the data beingread from the optical disc, without decoding, is merely used todetermine whether data errors occurred. Thus, the overall process runsvery quickly.

Firstly, the optical disc is driven to rotate, and the pick-up head isarranged to move from inner tracks to outer tracks, as shown in step110.

Then, determine if there are seek errors, as shown in step 120. If theoptical disc contains regional contaminant, such as a serious scratch ora large stain left by a felt pen, then the tracks on the optical disccan not be located properly, and seek errors will result. Thus, in theevent of seek errors, the region where seek errors occurred is marked asan error region, as shown in step 130.

Then, step 140 is performed to determine whether the region that thelaser is focused on is a data region or not. Since there are othernon-data regions on the optical disc, such as lead in/out area, gapsbetween audio tracks, the non-data region will be mistaken as havingmany data errors when the laser light is focused over these regions.Thus, data error counts are only enabled if the laser light is focusedover the regions of interest, namely, the data regions, as shown in step150. Otherwise, step 150 is skipped.

Then, step 160 is performed to determine whether the step of detectingdata errors has completed. If not, then the method is returned to step110 to repeat the steps and continue detecting the optical disk. Themethod according to this embodiment is not only limited to detectingdata errors on the entire optical disk, but can also be applied fordetecting error information on particular regions of the optical disc,such as only in detecting error information on the outer tracks of theoptical disk, since the dye on the outer tracks are comparably lessstable and are more likely to cause data errors.

By performing the method of detecting optical disc error informationaccording to the embodiment, users can acquire the data errorinformation distributed over every region of an optical disc, namely,the error information of C1 and C2 located on every region of a CD, andthe error information of PI and PO located on every region of a DVD.Moreover, users can also acquire the locations of error regions. Theusers can thereby determine the quality of the optical disk or theoptical disk drive, and the compatibility between the optical disk andthe optical disk drive based on the error information.

The detecting method can also be applied in the determination of opticalpick-up head tilt angles. To enable better read/write quality, theoptical pick-up heads of DVD recorders are capable of makingmicro-adjustments. Conventionally, after the optical disc drives aremanufactured, the optimal tilt angles are determined manually bypersonnel using instruments. However, this method of determining tiltangles does not allow much flexibility, and manufacturers bare a costburden towards the excessive use of human resources and high instrumentscosts.

FIG. 2A is a flow diagram illustrating a method of determining opticalpick-up head tilt angles by applying the method of detecting opticaldisc error information according to the invention. First, an initialtilt angle is set, as illustrated in step 210. Then, based on the methodof detecting error information indicated by FIG. 1, the errorinformation is detected while the pick-up head is adjusted to the tiltangle, as shown in step 220. Then, the tilt angle and the errorinformation entries are recorded, as shown in step 230.

Next, step 240 is performed to determine if there are enough entriesrecorded. If not, then the method is returned to step 210. Otherwise,step 250 is performed. Whether there are enough entries is determined bythe level of precision that users demand, and for example, if theentries required are equal to 10, then steps 210-230 are performed 10times.

Lastly, from the entries recorded, an optimal tilt angle is determined,as shown in step 250. Tilt angles are related to the error information,as shown in FIG. 2B, showing a graph plot of the recorded entries. Fromthe figure, it can be observed that the least amount of errorinformation is recorded while the optical pick-up head is at tilt angleA, and moving away from angle A in either direction, an increasing dataerrors trend is observed. Thus, from FIG. 2B, angle A is determined asthe optimal tilt angle.

In addition, the method of determining tilt angles according to theinvention can be applied for adjusting settings of optical disc drives,before the optical disc drives are being shipped out from themanufacturing site. By directly using the program within the firmware todetermine and adjust tilt angles, thereby reducing the time required foradjusting setting, the conventional involvements of humans andinstruments can be eliminated. While performing step 220 duringdetermining tilt angles, error information detection does not have to beperformed on the entire region of the optical disk, but rather, only oncertain regions of the optical disk, whereby the detecting speed can beincreased while maintaining precision.

The method of determining tilt angles according to the invention canalso be performed while the optical disc drive is in operation. Throughadjusting the tilt angles in response to the optical disc or theoperation environment, a better read quality can be achieved. The tiltangle adjustments can be performed when the optical disc is insertedinto the optical disc drive, or in real time during the read operationof the optical disc drive.

FIG. 3 shows a flow diagram of a method of detecting address errorinformation on a blank optical disc. First, step 310 is performed,driving the optical disc to rotate and the pick-up head to move frominner tracks to outer tracks to read the optical disc. Then, step 320 isperformed to detect whether an address error occurred. If yes, thenaddress error counts are added, as shown in step 330. Else, step 340 isperformed to determine whether detecting is complete, such as whetherdetecting the entire optical disk is complete. If not, then the methodis returned to step 310, else step 350 is performed to output theaddress error information.

The method of detecting optical disc error information according to theembodiment of the invention can be used to detect blank and non-blankoptical discs, and can be applied for adjusting tilt angles of theoptical pick-up heads in the optical disc drives.

While the invention has been described by way of example and in terms ofa preferred embodiment, it is to be understood that the invention is notlimited thereto. On the contrary, it is intended to cover variousmodifications and similar arrangements and procedures, and the scope ofthe appended claims therefore should be accorded the broadestinterpretation so as to encompass all such modifications and similararrangements and procedures.

1-4. (canceled)
 5. A method of determining an optimal tilt angle for anoptical pick-up head, comprising: determining a plurality of tiltangles, wherein the tilt angles are substantially different from oneanother; reading an optical disc according to each of the tilt angles;generating a plurality of sets of optical disc error information foreach of the tilt angles; and determining the optimal tilt angleaccording to the sets of optical disc error information.
 6. The methodaccording to claim 5, wherein the optimal tilt angle is selected fromthe tilt angles that has least errors in the corresponding optical discinformation.
 7. The method according to claim 5, wherein the step ofgenerating a plurality of sets of optical disc error informationcomprises: while reading a data region of the optical disc, recordingdata error information, the data error information comprising an errorcount and a corresponding data error location, and outputting theoptical disc error information according to the data error information.8. The method according to claim 7, wherein the step of generatingoptical disc error information further comprises: determining whether aseek error occurred, if yes, recording a seek error mark; and outputtingthe optical disk error information according to the seek error mark. 9.The method according to claim 5, wherein the step of generating opticaldisc error information comprises: determining whether an address erroroccurred, if yes, recording an address error information, comprising anaddress error count and a corresponding address error location; andoutputting the optical disc error information according to the addresserror information.